This invention relates generally to conveyors for bulk material and more particularly to a conveyor of this type which comprises a belt conveyor forming a tube in which the bulk material is conveyed in an upward direction from an entrance end at a lower portion of the belt conveyor.
Conveyors having double conveyor belts which over at least part of their extension are in face-to-face relationship and travel in unison, are advantageous for providing rapid and closed conveyance of bulk material over conveyance paths of both vertical and horizontal extension. This type of belt conveyors is disclosed for instance in U.S. Pat. Nos. 3,319,776 to G. Bechtloff et al and 3,618,746 to P. D. Suloff. In the belt conveyors described and shown in these patent specifications the material is supplied to a horizontal section of one belt. As a result, the arrangement will necessarily be relatively bulky at the point of supply, for which reason a belt conveyor of such a design is not suited as a vertical conveyor, especially not in narrow premises.
Further, it is previously known from U.S. Pat. No. 4,230,221 to Isaac Beresinsky to use for the supply of bulk material to a vertical belt conveyor a vane wheel which throws the material in between the belts of the belt conveyor. Said vane wheel does not operate directly in the bulk material depot, from which vertical conveyance is to be effected, but receives the bulk material either directly from a horizontally extending screw conveyor or via a vertically extending screw conveyor which delivers the bulk material to a bin from where the vane wheel throws it into the entrance end of the belt conveyor. In these cases also the conveyor requires relatively ample room at the entrance end and moreover the material changes its direction of motion at the entrance point. In the case of a horizontal screw conveyor the motional pattern of the entrance end is restricted to directions transversely of the longitudinal axis of the screw conveyor.
For the conveyance of bulk material from narrow premises it would be desirable if the material could be supplied directly to a downwardly directed end of a belt conveyor of the above-mentioned type, which necessitates that the flow of material is moved with a certain force up to the belt conveyor end for further upward conveyance.